Techniques are known in the art for providing carry-over control in combining high and low order binary number strings. Prior carry-over control techniques for use in, for example, arithmetic coding and decoding, are described in U.S. Pat. No. 4,463,342 issued July 31, 1984 and an article entitled "A Multi-Purpose VLSI Chip For Adaptive Data Compression of Bilevel Images", IBM Journal of Research and Development, Vol. 32, No. 6, Nov. 1988, pages 775-795. Another carry-over control technique is described in an article entitled "Arithmetic Coding for Data Compression", Communications of the ACM, June 1987, Volume 30, Number 6, pages 520-540.
Disadvantages of the techniques disclosed in the U.S. Pat. No. 4,463,342 and in the IBM Journal article, noted above, are that they incur a compression performance penalty in a transmitter/encoder and an increase in the complexity of a corresponding receiver/decoder. These disadvantages result because of the need to insert so-called control characters, i.e., bits, in the transmitter/encoder bit stream and the need to remove the control characters in the corresponding receiver/decoder.
The technique disclosed in the "Arithmetic Coding For Data Compression" article has the disadvantage of significantly increasing the computational complexity of the encoder/decoder. This increase in complexity results because per bit processing of information is required in the encoder and decoder.